Foundry Lottery

A decentralized lottery smart contract built with Foundry, following Cyfrin Updraft course. This project demonstrates how to create a secure and efficient lottery system on the Ethereum blockchain using Chainlink VRF for randomness.

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Features

• Decentralized Lottery System: Secure and transparent entry process.
• Random Winner Selection: Uses Chainlink VRF for unbiased randomness.
• Automation: Employs Chainlink Automation for periodic upkeep and lottery resets.
• Customizable: Adjustable lottery parameters like entry fee and duration.

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Prerequisites

Before you begin, ensure you have the following installed:

• Foundry
• Node.js and npm
• A blockchain wallet (e.g., MetaMask)
• Access to a testnet like Sepolia or Polygon Amoy

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Setup

1. Clone the repository:

   git clone https://github.com/KMean/foundry-lottery.git
   cd foundry-lottery

2. Install Dependencies

   forge install

3. Set up environment variables: Create a .env file with the following:

   SEPOLIA_RPC_URL=your-sepolia-rpc-url
   AMOY_RPC_URL=your-amoy-rpc-url
   CHAINLINK_VRF_SEPOLIA_SUBSCRIPTION_ID=your-sepolia-chainlink-vrf-subid
   CHAINLINK_VRF_AMOY_SUBSCRIPTION_ID=your-amoy-chainlink-vrf-subid
   ACCOUNT=your-account-address-used-to-create-subids

4. Compile Contracts:

   forge build

5. Create an account with cast

   cast wallet import your-account-name --interactive
   Enter private key:
   Enter password:
   `your-account-name` keystore was saved successfully. Address: address-corresponding-to-private-key

Deployment

To deploy the contract on Sepolia, run:

forge script script/DeployRaffle.s.sol --rpc-url $SEPOLIA_RPC_URL --account your-account-name --broadcast

Testing

Run unit tests to ensure everything is working:

forge test

For coverage:

forge coverage

Usage

1. Enter the Lottery: Users can enter by sending the required entry fee to the contract.

2. Automated Winner Selection: The lottery uses Chainlink Automation to trigger the winner selection when the interval time has passed.

3. Winner Selection: The winner is selected using Chainlink VRF and receives the full lottery balance.

Acknowledgments

• Cyfrin Updrafts: For providing great courses and comprehensive course materials.
• Foundry: For the robust development framework.
• Chainlink: For secure randomness and automation.
• Alchemy: For providing excellent node-as-a-service for testing.

License

This project is licensed under the MIT License.